The present invention relates to a cassette loading and unloading device for adjustably accommodating cassettes of different sizes which accommodate films or the like of different sizes, for removing the film from a loaded cassette and delivering the film to either a magazine which can store a stack of films or an automatic developing machine, and for automatically unloading a loaded cassette after the film is taken out therefrom.
Heretofore, a film which has been exposed to an X-ray image and which has not yet been developed is accommodated in a cassette in a light-shielding condition, and the cassette is loaded into a given device. After the film is taken out of the cassette and placed in a magazine, the empty cassette is unloaded from the above device, or alternatively the exposed film is fed from the cassette to an automatic photographic processor through a film removal device. Such a device is widely employed in mammographic imaging systems.
The relationship between the device and a mammographic imaging system will be described below with reference to FIG. 1 of the accompanying drawings.
Films a which are stacked in an envelope are placed in a magazine b in a bright room, and the magazine b is then accommodated in a loading device c. An empty flat cassette d is also accommodated in the loading device c. If films a' of a different size are also involved, the films a' are placed in a magazine b' in a bright room, and the magazine b' and an empty cassette d' are accommodated in another loading device c'. In the loading device c, an unexposed film a is transferred from the magazine b into the cassette d by a feed mechanism (not shown). Then, the cassette d which accommodates the film a in a light-shielding condition is taken out of the loading device c. Likewise, an exposed film a' is transferred from the magazine b' into the cassette d' which is taken out of the loading device c'. The films a, a' in the flat cassettes d, d' are used to photograph an object such as a woman's chest to check for a breast cancer, for example.
The cassettes d or d' (referred to as a "cassette f), which places the exposed films therein, is then accommodated in a film removal device g associated with an automatic photographic processor. Alternatively, the cassette f is placed in a film storage device h which is not associated with an automatic developing machine. In the film storage device h, the films are stacked in a magazine i by a film delivery mechanism. Then, the magazine i is accommodated in a film feed device j associated with an automatic photographic processor, and the films are taken out of the magazine i and sent to the automatic photographic processor. The films are thereafter developed into X-ray photographs by the automatic photographic processor.
One conventional film cassette loading and unloading device includes belts and roller groups for delivering a cassette into and out of a film storage device. Such a belt-and-roller arrangement can automatically load and unload cassettes. However, the distances between the belts and the roller groups have to be adjustable in order for the film cassette loading and unloading mechanism to handle cassettes of different sizes. The automatic film cassette loading and unloading device is therefore complex in structure, expensive to manufacture, and cannot be greatly reduced in size.
There has also been proposed a cassette loading and unloading device which receives a manually inserted cassette and delivers the received cassette. The cassette loading and unloading device has a cassette guide which allows an one of a plurality of cassettes to be manually inserted into the film storage device when a lid of the cassette loading and unloading device is opened. Inasmuch as a desired cassette is manually inserted, the insertion process is timeconsuming, laborious, and always requires manual intervention.
When films are to be taken out of cassettes of different sizes, lock means associated with the cassettes for keeping the cassettes shielded from light have to be unlocked individually. To this end, the cassette loading and unloading device must have unlocking means corresponding respectively to the lock means of the cassettes. Since the different cassettes have different longitudinal and transverse dimensions, the cassette loading and unloading device would be quite complex in structure and large in size if respective unlocking means were provided positionally corresponding to the lock means of the different cassettes.
Actually, therefore, a dedicated cassette loading and unloading device is employed with respect to cassettes of one size. If differently sized cassettes are involved, different cassette loading and unloading devices matching those cassette sizes have to be employed.
After the film has been taken out of a cassette in a cassette loading and unloading device, the cassette needs to be unloaded from the cassette loading and unloading device. Before the cassette is unloaded, a lid of the cassette which has been open for the removal of the film therefrom must be closed because it would be cumbersome to unload the cassette with its lid open and the opening for the unloading of the cassette would have to be large enough to allow the passage of the cassette with the open lid.
Some prior devices employ movable suction cups or pads for opening the lid of a cassette before it is unloaded. The cassette lid is sucked by the suction cups under vacuum and angularly displaced into a closed position.
The cassette loading and unloading devices which incorporate such suction cups are structurally complicated as they require a vacuum generator and tubes connecting the vacuum generator to the suction cups. Another problem is that the path of the movable suction cups may be limited by other components positioned near the suction cups.